The entirety of this article cannot be reproduced here. Its logical meat
is missing: a detailed exposition of Bertrand Russell's attempts to banish the
paradoxes of set theory through the theory of types and the prohibition of self-reference,
as well as treatments of related problems by other logicians and mathematicians.
Please consult the original article to connect these issues in mathemathical
logic to the author's philosophical thesis.

I have long been fascinated by the question of the relationship between
formalization and the extra-formal dimension of abstract thought. This article
encapsulates the conceptualization I am after like no other. The philosophical
highlights of the author's argument are here excerpted.  R. Dumain

What on Earth does metamathematics have to do with dialectics?
One may justifiably find the association of these concepts dubious. Metamathematics,
the foundational science of mathematics, seeks to grasp the conditions under
which a contradiction-free science of quantity is possible. The following essay
would like to show, in taking up the foundational reflections proper to metamathematics,
that the principal anchoring of consistent mathematical objectivations presupposes
a ground which not only founds these, but at the same time surpasses them in
principle. Such an immanent movement of the principal presuppositions of a spiritual
construct is what Hegel understood by a dialectical development. Yet it is not
my concern here to provide a Hegel-interpretation, but rather to demonstrate
a development in the Hegelian sense with respect to a science. Only what is
astonishing here is that it should be possible to show such a development precisely
with respect to mathematics, a form of the human spirit extremely remote from
dialectics. And yet this development also has to be understood dialectically:
knowledge can neither avoid the quantitatively unambiguous nor be content with
it.

[p. 191]

‘God’, ‘freedom’, and ‘self-consciousness’ do not constitute
an arbitrary selection of concepts from the history of occidental philosophy.
Such is virtually impregnated with self-reference. Precisely its central concepts
possess a reflexive structure. That means, however, that Russell’s prohibition
has far-reaching consequences for the whole of philosophy. Were Russell’s insight
that every self-reference robs the concept in question of any sense, to prove
to be unconditionally true, then the central concepts of the philosophical tradition
would be invalid. The reconstruction of a contradiction-free mathematics on
the basis of a general prohibition of self-reference means that the theory of
the foundations of mathematics, which is plagued by antinomies, can be rebuilt
only on the ruins of metaphysics.

[p. 198]

It is to Russell’s merit that he elevated this principle of
non-reflexibility, of the objectivistic spirit in mathematical formalism, expressly
to the rank of a principle. Here Russell’s principle radicalizes Cartesian dualism
to the effect that now objectivity is not only encompassing with respect to
subjectivity, but rather there is no longer any mediation between the mathematically
graspable objectivity and self-conscious subjectivity; rather, a justifiable
sense may not in general be attributed to any spiritual construct with a self-reflexive
structure.

]p. 199]

On the basis of the foregoing reflections, we may now draw the conclusion that
the prohibition of circularity itself, in that it excludes every self-reference
without exception, is self-referential. That means, however, that Russell’s
insight into the senselessness of self-reference in fact does free the mathematical
formalism of the antinomy by means of his prohibitive principle, but the price
to be paid for this guarantee of freedom from contradiction is that the prohibition
of circularity is equivalent to the antinomy.

pp. 200-201

In this metaphor, the modern principle of irreflexivity, the prohibition of
circularity, takes the place of antiquity’s absolute foundation. Their relation
is here simultaneously one of correspondence and extreme opposition: the "hypothesis"
of the theory of types does not stand in a relation of deductive dependence
on the prohibition of circularity—nevertheless the prohibition of circularity
necessarily motivates the irreflexivity of the theory. Contrary to the self-reference
of the ideal foundations of the ideas, the prohibition of circularity is a principle
of irreflexivity; as such, however, it is at the same time necessarily self-referential.

The relation of principle and theory in modern science is radicalized
in Russell’s foundation of science and at the
same time transcended toward knowledge in the ancient sense.

[pp. 201-202]

The formal restriction of comprehension to irreflexive sets
would thus introduce a source of difficulty into the deductive-axiomatic order.
Precisely for this reason, a restriction of comprehension by Russell’s vicious-circle
principle must remain outside of the formal-deductive order in a so-called motivating
relation. The formal-deductive order is thereby reduced to a mere objectivation
within mathematics, which expressly presupposes the informal mathematical intuition
of the subject.

Put another way: formalized, the prohibition of circularity
would be an antinomy.

[pp. 202-3]

Incidentally, it is noteworthy that a consistent
formalization is by no means the only way in which a concept can be
objectivated. For instance, the contemporary fine arts,
by means of a realistic reflection, have also depicted reflexive structures.
It is exactly at this point that Realism turns into Surrealism.

Magritte’s "La reproduction interdite" from 1937
shows a man standing before a mirror who sees reflected, instead of his
face, his back. The work can be understood as an expression of
the vicious-circle principle.

The Dutch graphic-artist M. C. Escher likewise worked on the
problem of reflexivity ("Still Life with a Convex Mirror," 1934; "Hand with
a Reflecting Sphere," 1935; "Still Life and Street," 1937; "Three Spheres,"
1946). As far as I know, he was the only one in the fine arts who succeeded
in comprehending the singular point of reflection in the identity of just one
reflection, instead of in an infinitely regressive series of mirror-refractions:
"Print Exhibition" from 1956 shows a gallery visitor standing before a print
showing in turn a port town and in the town the same gallery with the same visitor
standing before the same print. Now Escher’s mapping is most remarkable given
the fact that the lithograph in front of the viewer in the picture is identical
with the lithograph in front of us. In other words, a part of the depiction
is identical with the whole, or the viewer views his viewing. Escher proceeded
in this objective realization of self-reflection as follows: he depicted a view
of a city (including the gallery and therein the views of the city, infinitely
reflecting themselves in views of the city), originally drawn from the central
perspective, subsequently with the help of a projection expanding cyclically
clockwise, whereby the infinite series of depictions (including the gallery
visitor) are telescoped in one another and thus are simultaneously identical
and not identical with themselves. Noteworthy is that the network of the cyclical
projection in Escher’s subsequent depiction seems to correspond to an elliptical
geometry.

An objectivation of self-reference and therefore also of the
prohibition of circularity is thus perfectly possible, whereas a mathematically
objection-free, i.e., contradiction-free, formalization is hardly possible.
Therefore the prohibition of circularity guarantees that the theory of types
is contradiction-free only via an informal motivating relation to the
latter’s formal-deductive order. Thus there is at least one proposition of mathematics
whose principal relevance cannot be expressed as a formal proposition of the
theory of types. This conclusion differs from the result maintained by Gödel
as a corollary to his incompleteness theorem, insofar as the role of the consistency,
which can be expressed formally only incompletely, is actually taken up in Russell
by the vicious-circle principle: our faith that arithmetic can be represented
without contradiction by the formally axiomatized theory is grounded on the
vicious-circle principle.

[p. 204]

The suggestion by Boudrie and Kluyt contains a consistent development
of what had remained only implicit in the foregoing. As we saw, the prohibition
of circularity is free of self-reference if and only if it is self-referential.
That means: reflexivity may be eliminated only by reflexivity itself; to the
extent that everything is irreflexive, self-reference immediately appears again.
Irreflexivity entails reflexivity as its shadow, which it is unable to shake
off. The principle of an irreflexive completeness itself yields a logically
necessary self-reference. Were mathematical formalization the only way to objectivate
anything that is possible, then mathematics would not be possible.

Yet this necessary self-reference of excluded self-reference,
this negation of a negation, in an Hegelian parlance, is completely empty. It
has no determination other than self-reference. It requires that exposition
which does not only arise from the reductio ad absurdum of a complete
irreflexivity. The formal necessity of self-reference retains for the moment
the emptiness of the (contradiction-free) reversed paradox of the liar, who
says: "This sentence is true." Yet it points to a void as the logical embedding
space of metaphysical concepts.

[p. 205]

Finally one could respond to Boudrie and Kluyt’s circular prohibition
of circularity by saying that, beyond the credit due to the acknowledgment of
self-reference as a necessary moment of non-self-reference, their prohibition
not only suffers from the emptiness of its own reflexivity, but also from an
abstractness with which it sets circularity and freedom from circularity in
opposition to one another. For one not only has to give up abstract freedom
of circularity, one also cannot hold fast to an abstract self-reference without
it turning into its opposite. The antinomies of mathematical circularities were
not the first to make this manifest, but rather Hegel’s critique of abstract
self-consciousness already did so.Self-consciousness is possible
only insofar as it, instead of ridding itself of its own negativity, refers
its negativity to itself and posits it as self-sublating.

Russell’s vicious-circle principle actually achieves
that. If we retain the prohibition of circularity, then we also retain its self-reference,
which also includes the truth of its antinomic nature.

The Opposition between the Prohibition of Circularity and
Formal Theory

Let us raise anew the question of how the prohibition of circularity
as a principle of an antinomic, self-referential nature is to be grasped in
relation to formal mathematical theory. The prohibition of circularity and formal
theory are obviously opposed to one another, since the latter’s freedom from
contradiction is enabled only by the (antinomic) exclusion of self-references.
Now what kind of opposition is this?

It is not abstractly negative, if we understand thereby every
kind of relation of two opposed terms which unambiguously exclude one another
in an essential respect. In view of the essential definition of circularity,
formal theory is in fact unambiguously circle-free; the prohibition of circularity
itself, however, is not unambiguously circular, but just as circle-free. Via
Aristotle’s primary determination of opposites, we fail to get an immediate
hold of the said relation. I can show this here only very briefly for his four
oppositions and on the assumption of the Aristotelian theory.

The prohibition of circularity and formal theory are not contradictorily
opposed, since neither of the opposed terms can be asserted to be something
positively determined in itself; nor can either of the two be asserted to be
constantly true, while the other is false. Their opposition is just as little
contrary, since the circularity and its negation cannot be understood as specifications,
e.g., of self-referential or formalizable concepts. This is already clear in
that the prohibition of circularity itself possesses the character of a concept.
Thereby the prohibition of circularity does not fulfill the requirements of
Aristotle’s theory of definition, since otherwise the genus could be predicated
of the specific difference. The relation of the prohibition of circularity to
the mathematical concept falls outside of a genus-species order. But neither
can we understand the opposition privatively, for instance, as if the prohibition
of circularity lacked freedom from circularity as something that would, according
to its own nature, belong the former.

The question as to whether the relation of the
prohibition of circularity to the mathematical concept may
be understood as a relative opposition is even more difficult to answer. First,
the terms of the relation, here thought as principle and as
something principled, exist only in their constitutive relation.
In other words, if we wish to think the relation
of principle to principled as a relation, then we have to pass over the Aristotelian
doctrine that a relation is always accidental and we may no longer
understand the relation as a category in the usual sense. Furthermore, we have
to consider whether the relata are so opposed in their relation that that determination
attributed to one of the terms of the relation, is lacked by the other. This
constitutive determination, the absence of circularity, is in fact
unambiguously attributed to the mathematical concept; but neither circularity
nor its absence are unambiguously attributed to the prohibition of circularity,
but rather both simultaneously in the same respect.

This state of affairs calls for a negation that
does not correspond to the traditional four opposites and that does not
exclude what is negated, but rather negates in such a way that it simultaneously
embraces what is negated. This preserving negation is Hegel’s
concrete negation.

The concept of such a "relative" opposition is then to be modified,
however, precisely in the sense of the dialectical relation, namely: the opposed
relation should no longer be thought to exist substantially outside of their
relation.

Finally, the prohibition of circularity is non-formal
in the sense that it in fact does not obey the prohibition of self-reference
stated in it, but certainly founds here a region of extensive non-ambiguity.
It thereby makes possible the region of the mathematical, in which the freedom
from contradiction prevails. The precept of the freedom from contradiction and
the prohibition of self-reference in fact prevail in this region, which
is embedded in a non-formal region, in which certainly no precept of
contradiction prevails. The prohibition is precisely sublated and not
excluded, for the abstract negation would make itself known time
and again only as a mathematical form of understanding,
i.e., it would only reproduce the characteristic problematic of this form, instead
of removing it.

It seems significant that just in this form of understanding—which
understands itself as an absolute opposition to speculative reason— namely,
in the mathematical, the necessity of Hegel’s concrete negation can be
demonstrated. Its truth is more binding the less it was intended. Dialectical
negation arises from mathematical objectivation itself, as a necessary condition
of the latter’s own possibility.

This impossibility of an exhaustive formalization of several
basic concepts of mathematical theory is familiar from the works of Gödel
and Tarski. The informal sense of negation, which formal mathematics presupposes
in its relation to the prohibition of circularity, was more precisely determined
thereby.

[pp. 206-8]

In the foregoing we have found, in reference to the question
of how the relation of the principle of excluded self-reference (the "prohibition
of circularity") to the formal-deductive order of mathematical theories can
be grasped, that the prohibition of circularity enables formal theory’s freedom
from contradiction in that it simultaneously withdraws from this order: it is
not a theorem of formal theory. It is self-referential, according to its structure
antinomical, transgresses the distinction between syntactic and semantic references,
and encompasses the formal-mathematical objectivation in a concrete-dialectical
opposition to the latter.

[pp. 209-10]

It is an historically noteworthy fact that the
difficulty of granting formal expression to Russell’s prohibition
of circularity was never discussed. It remained simply unconscious, as if a
state of affairs were repressed which could not be addressed until Gödel
appeared and therefore was banished from mathematical consciousness.
For would it not have been obvious to present Cantor’s axiom of comprehension
now in an expressly qualified form? For instance: "Every set can
be understood in turn as an element of sets insofar as it does
not include itself as an element"? Such a proposition, however,
would lead to difficulties and was consistently banned by
Russell as nonsense. This according to a principle whose formal inexpressibility
was subsequently accepted somehow without people becoming particularly
thoughtful about this state of affairs.

[p. 210]

Metamathematics seems to be confronted with the choice between
an incomplete or contradictory self-foundation. This means, however: it has
to opt either for a rejection of a thorough self-comprehension or for a self-relativization.
In the proper sense, one is not at all free to opt for the first possibility,
since its basis lies in its unfoundability. In other words, its possibility
as a mere decision stands or falls with the deed, whereby its own grounds of
justification are driven into the subconscious. One can omit the thorough self-foundation
de facto; a mathematically acceptable foundation for this omission, however,
would be self-destructive. By contrast, a decision in favor of self-relativization
means that mathematics has sublated itself as a theory of everything possible
and founded itself as one possibility of the human spirit.

[p. 211]

The principle of circularity is, so to speak, a regulative
principle for formal-mathematical objectivation also outside of type-hierarchies
in which the prohibition of self-reference appears as such. In axiomatic set
theory, there is in fact no prohibition of circularity, but if one asks a student
of axiomatic set theory why he thinks that his system is free of the antinomies,
he could answer with good reason that the operations which allow for the formation
of certain sets are chosen such that, e.g., Russell’s class and other self-references
can no longer be formed. Therein lies the reason for his confidence. At the
same time, it is the reason for my assumption that a prohibition of self-references
in the contemporary dialectical transformation of the ancient meaning of [Greek
word] is a principle of mathematics, which, in that it in fact guarantees formal
freedom from contradiction, simultaneously withdraws from mathematical objectivation
and hints at a spiritual region in which, along with quantity, other categories,
such as, e.g., ‘freedom’, ‘life’, justice’, and ‘person’, are also founded.